The oxidation of gelatines to destroy photographically active substances, i.e. to make them inert, and to remove bacterial impurities or to lighten the color of the gelatine is known, hydrogen peroxide, per acids, such as performic acid, peracetic acid, per iodic acid, chloramine T (N-chloro-p-toluenesulfonic acid amide sodium) and the like being used as oxidizing agents.
It is known from EP-A-0 227 444 and EP-A-0 228 256 that it is of advantage to use oxidized gelatine for the production of tabular grain silver halide emulsions, particularly where the emulsion has a high chloride content. However, gelatines of this type have the disadvantage that they lead to an unacceptable increase in fogging.